ONE is possibly the greatest scientist who ever lived, and the other is a maverick physicist from Adelaide.

But Reg Cahill says he can prove Albert Einstein and his hundred-year-old theories of relativity are wrong.

The problem for Professor Cahill is that many of his contemporaries line up with Einstein.

"I've been treated with utter contempt and hostility," he told The Australian. "This is pretty shocking stuff -- but it's what you'd expect."

In 2002, Professor Cahill started to question what he thought were anomalies in Einstein's theory that time and space are relative.

"They all agreed with one another and they were all indicating a huge speed difference in different directions," he said. "When you find out the speed of light differs, the whole Einstein theory starts collapsing."

"We know now the speed of light at approximately 300,000km per second is relative to space itself. Before it was always relative to the observer."

Professor Cahill said that debunking the Einstein theories would lead to new discoveries in physics and greater understanding of phenomena that could not yet be fully explained. "There are some incredible discoveries being made," he said. "We're discovering some properties about space that are awesome."

Those discoveries include the speed at which the solar system is travelling through space and the detection of gravitational waves.

"The rotation of galaxies has always been a problem -- we now understand how they work," Professor Cahill said.

"The outer part of spiral galaxies go around about 10 times faster than Einstein's theory permits, so people invented dark matter to account for extra gravitational pull.

"They've spent years and millions of dollars looking for it -- but it doesn't exist."

Over the past 100 years, physicists have conducted experiments to test if the speed of light is constant. Professor Cahill says they obtained definitive results but ignored them because they feared they would be shouted down for questioning Einstein. "It's staggering that the concept of physics has been built on a mathematical illusion."

But physicist Paul Davies of Macquarie University and the Australian Centre for Astrobiology said Einstein's theories of relativity had been tested, and there was no evidence to suggest they were wrong.

"I'm not aware of any experimental evidence that suggests Einstein is wrong," Mr Leinweber said. "Every experimental measurement I'm aware of is in accordance with Einstein's premise that the speed of light is the same in all frames."

But support for Professor Cahill is growing. The Australian Research Council gave a $60,000 grant for his research, and the world's largest particle physics laboratory -- CERN in Switzerland -- has donated $100,000 worth of optical fibres.